They say slow and steady wins the race and zoo keepers are holding out hope that this is still the case for a pair of giant tortoises who have failed to mate after four decades.
Dubbed ‘Britain’s most reluctant lovers,’ Biggy and Twiggy have lived together at Bristol Zoo since 1975 and today were given a clean bill of health at their first weigh-in in five years.
Giant tortoises usually start breeding when there are enough around to force competition so the zoo has recently introduced two more tortoises into their enclosure to encourage the pair to mate.
Slow and steady: Vet Rowena Killick checks 63-year-old male giant tortoise Biggy for the first time in five years in which he weighed-in at 220lbs
Female Twiggy, who is 63 weighed-in at 220lbs, 22lbs more than in 2008 but it was 68-year-old male Biggy who really tipped the scales, weighing-in at 440lbs, 50lbs more than in 2008.
More...
Camouflage cats: Hilarious snaps show crafty felines blending into their surroundings to avoid detection
EU ban on pesticides linked to bee deaths moves one step closer despite UK government's resistance
Clash of the titans: Amazing pictures of killer whales attacking pod of sperm whales twice their size on hunting expedition
Zoo spokesman Catherine Foster said: ‘Maybe he has just been taking his time, playing the long game.
‘There has been mating actually, but breeding is work in progress.
Tipping Twiggy: The pair of giant tortoises were given a clean bill of health after their weigh-in and health check which included tipping female Twiggy on her side
Slow moving: Biggy (pictured) and Twiggy have been living together at Bristol Zoo since 1975 but have yet to reproduce
‘We're still waiting for the fairy tale slow patter of little feet.’
Tortoises live in a heated enclosure where they spend their days munching high-quality hay and the occasional treat of dandelion or spring greens.
While they look harmless enough, the lumbering hulks lose their gentle temperament when they are in the mood for mating.
Ms Foster said: ‘Giant tortoises prefer to go over things than around them so if you're ever standing nearby one watch your toes.’
Native to Seychelles in Africa, the giant tortoise has a lifespan of at least 100 years, even up to 150. They grow steadily for the first 40 years of their lives and can weigh up to 560lbs.
Waiting for the slow patter of little feet: Zoo keepers are hopeful that, even after almost four decades, the pair will mate and reproduce
Large tortoises are among the longest-lived animals on the planet, with some individuals thought to be over 200-years-old, but this is difficult to verify because they tend to outlive their human observers.
Their shell does not serve as protection from predators as they have no predators on the islands where they evolved. They are usually silent but mating males make a hollow groaning sound that can be heard hundreds of feet away.
Tortoises exploit many different kinds of habitat including grasslands, low scrub, mangrove swamps, and coastal dunes.
Competitive nature: Giant tortoises usually start breeding when there are enough around to force competition so the zoo recently introduced two more tortoises into their enclosure to encourage Biggy (pictured) and Twiggy to mate
Last month 18-year-old Adam Steff stole an endangered tortoise worth £2,000 from a safari park and sold it on Facebook - for a paltry £30.
The teenager took Flo, a 4.5lb juvenile Aldabra giant tortoise, from Woburn Safari Park in Milton Keynes after he wandered into her enclosure while drunk.
The 18-year-old originally tried to sell Flo for what she was worth, then accepted an offer of just £30 for the tortoise - a specimen of one of the world's rarest species. Police arrested Steff, a bricklaying student, after matching his DNA to saliva on a beer can left at the scene.He was ordered to carry out 80 hours of unpaid work and also given a curfew from 7pm to 7am, to last two months.